共查询到20条相似文献，搜索用时 31 毫秒
1.
R. Yu. Udovitskiy Yu. V. Sotnikova M. G. Mingaliev P. G. Tsybulev G. V. Zhekanis N. A. Nizhelskij 《Astrophysical Bulletin》2016,71(4):496-505
We present the automated systemfor estimating the parameters of radio sources observed on all available continuum radiometers (two receiving facilities of secondary mirrors No. 1 and No. 2 with a total of 30 radiometers) developed at RATAN-600 radio telescope and put into normal operation. The system is also used for the monitoring of the parameters of the antenna and receiving systems of RATAN-600 radio telescope, which is carried out using current measurements of calibration radio sources. 相似文献
2.
S. Kh. Tokhchukova 《Astrophysical Bulletin》2011,66(3):379-388
The development of observational equipment and software for processing and efficient representation of spectral and polarization
solar microwave observations on the RATAN-600 contributes to obtaining new information about the parameters of plasma at the
chromospheric and coronal levels. Current status of information system for RATAN-600 solar observations is described, which
is devoted to automatically capturing, storing, transmitting and processing the data and near-real-time publishing them on
the Internet. The user web interface for interactive search, visualization, and on-line analysis of the data is available
at . 相似文献
3.
V. M. Bogod O. A. Golubchina G. N. Zhekanis A. N. Korzhavin V. S. Kotel’nikov N. A. Nizhel’skij P. G. Tsybulev 《Astrophysical Bulletin》2007,62(4):360-368
We report the results of unique observations of the solar eclipse of March 29, 2006 over a wide radio-wavelength range from 1 to 50 cm made with the large RATAN-600 stationary radio telescope during the maximum eclipse phase performed using the method of the source transit across the fixed beam pattern. The multifunctional opportunities of the radio telescope allowed observations to be performed simultaneously in a part of the Northern sector of RATAN-600 and in the Southern-sector plus periscope mode using all the available receiving equipment at the corresponding secondary mirrors. At the time of maximum eclipse phase a narrow 1—3-arcsec wide crescent-shaped band near the North Solar Pole remained visible out of the entire solar disk covered by the Moon. We achieved high flux sensitivity, which allowed us to discover a large polar radio source located above the North Solar Pole and obtain detailed data on its radiation and spatial structure. Moreover, we detected optically thin radiation of the solar corona at the brightness-temperature level of several K or several tens of K. We find this radiation to extend beyond the solar limb out to the heliocentric distances of one solar radius. These data are unique in that they are not contaminated by scattered radiation of the solar radio disk, which usually shows up in ordinary observations. We are the first to obtain a detailed spectrum of the radiation of a high-latitude prominence at many wavelengths with a 1% frequency resolution in the microwave range, which allowed us to estimate its magnetic field at a number of levels in the lower corona. 相似文献
4.
We report the results of RATAN-600 radio telescope observations of the fine structure of the source of cyclotron microwave emission (SCMR) located in the solar corona above the main sunspot of NOAA11899 active region. Compared to earlier and mostly episodic observations of the SCMR, our regular observations with RATAN-600 radio telescope showed rather conclusively that the variation of the structure of the SCMR as a function of the angle of view in the present case is of geometric nature. The behavior of image variations generally agree with the computations performed by Gelfreikh and Lubyshev in terms of the simplest model of the solar atmosphere above the sunspot. The results of their computations are widely used for interpreting observations. 相似文献
5.
V. M. Gogod 《Astronomische Nachrichten》1992,313(2):97-100
The potential possibilities of RATAN-600 for solar studies are considered which are going on to be realized during the present maximum of solar activity. Different methods of an improvement of the characteristics of the antenna-receiver system are analyzed. These are: – realization of tracking the Sun during about 4 hours for a day and attaining temporal resolution up to some msec, – realization of radio-heliographic observations, – realization of a full spectral coverage of the radio telescope from 1,5 to 18 GHz with a frequency reslution up to 1–2 MHz, – combination of all possibilities mentioned above in an adaptable solar observing complex. 相似文献
6.
We report here the results of observations of two BL Lacertae-type objects, J2005+77 and J2022+76, using the RATAN-600 at frequencies 11.2, 7.7, and 4.8 GHz. We found variations of radio emission on timescales of one day and we are the first to discover a variability of this type for J2022+76.We compare our observations with long-term multifrequency radio observations of the same sources performed on RATAN-600 within the framework of other observational programs. We analyze the behaviour of variability of the two sources and provide arguments in favour of the preferred emission generation mechanisms for the objects studied. 相似文献
7.
We describe the technique and results of modelling the solar radio emission during the maximum phase of the solar eclipse
of March 29, 2006 on the RATAN-600. The aim of modelling is to refine the brightness temperature of the solar corona at the
distances up to two solar radii from the center of the optical disk of the Sun. We obtained the distribution of brightness
temperature in the vicinity of the coronal hole above the solar North Pole at the wavelength of 13 cm. The results of modelling
showed that brightness temperatures of the coronal hole at the distances greater than 1.02 RC (here RC is the radius of the optical disk of the Sun) is substantially lower than the expected average brightness temperature of
a typical coronal hole, and that of the quiescent Sun (below 30000 K) at the wavelength of 13 cm. The classical Baumbach-Allen
formula for electron density in a spherically symmetric corona agrees with the results of observations starting at distances
of (1.4–1.5) RC. 相似文献
8.
The refined data on the diffraction scattering of RATAN-600 allowed the telescope field of view to be increased substantially at large elevations. Amethod, which can be used to reconstruct the parameters of the sources passing at angular distances fromthe beamaxis that are several dozen times greater than the half-power width of the beam, is analyzed. The knowledge about wide scattering of RATAN-600 allowed the noise from background radio sources at zenith to be reduced by one order of magnitude and flux sensitivity of the radio telescope to be increased by the same factor without resorting to two-dimensional mapping. Methods for cleaning one-dimensional records of the RZF survey are suggested that use model scans based on the data of the NVSS survey and MHAT filtering. The latter proved to be an especially efficient tool for suppressing sky noise and identifying sources in the central section of the survey. The flux sensitivity of RATAN-600 is estimated with new opportunities taken into account. 相似文献
9.
V. M. Bogod 《Astrophysical Bulletin》2011,66(2):190-204
Regular upgrade of the RATAN-600 radio telescope has been completed in order to prepare the instrument for the studies of
the active Sun during the 24th solar-activity cycle. The upgrade included the improvement of the parameters of the multi-octave
solar spectral and polarization analyzer, realization of regular multiple observations, and the use of modern capabilities
for the representation and processing of observational data. In this connection, there appear to be sufficient reasons to
review the results obtained using the previous version of the receiving equipment and discuss the new capabilities in the
study of the physics of the solar atmosphere provided by the new analyzer. 相似文献
10.
In the paper we present the results of search for transient sources using the data from the surveys conducted onRATAN-600 at 7.6 cmin the time period of 1980–1994.We detected three events at a level of 3–5σ. A search for coincidenceswith detected transient events was carried out. Using the data from radio and optical surveys and the VizieR, SIMBAD, and NED databases, we made assumptions on the possible nature of these events. The first transient is probably associated with AGN activity, the second—with a cataclysmic GRB event or with a supernova, the origin of the third is not determined. The inference on the possibility of search for variable sources and transients using the data from the RATAN-600 blind surveys was drawn. Searching for transients, we have found twenty-two radio sources which are associated with the NVSS objects but are not included in the RCR catalog. Three of them turned out to be presumably variable. 相似文献
11.
S. Kh. Tokhchukova A. N. Korzhavin V. M. Bogod E. A. Kurochkin A. V. Shendrik 《Astrophysical Bulletin》2014,69(3):356-367
We report the spectra of the horizontal size of the beam pattern of the RATAN-600 radio telescope operating in the “Southern Sector with a Flat Reflector” observing mode computed in the geometrical optics approximation with allowance for the beam patterns of various primary feeds used in observations with the solar receiver facility in the 3–18 GHz frequency interval. In particular, we show that in the case broadband, spiral, or sinuous feeds are used, the width of the horizontal beam pattern of the antenna decreases with wavelength in the low-frequency part of the spectrum.We compute the spectra of the sizes of two compact local sources on the Sun, which show that the results obtained have to be taken into account when determining the parameters of local sources. 相似文献
12.
Radio astronomy studies of the solar atmosphere possess a very important, not duplicated by other methods, place in the study
of solar activity at all stages—from the birth of an active region until its collapse. A significant progress in these studies
can be achieved in the implementation of new technical possibilities, such as an increase in the sensitivity of radio telescopes,
a detailed spectral analysis over a wide frequency range, high temporal resolution and a broad coverage range in time. We
report about the implementation of regular observations with a new spectral and polarization high-resolution system SPHRS,
installed at the radio telescope RATAN-600.We describe the concept of the new system and the methods of its implementation. 相似文献
13.
M.G. Larionov 《Astrophysics and Space Science》1997,252(1-2):155-166
The sky distributions of sources in a RATAN-600 survey and a strip of the 87GB survey have been investigated. The presence of deviations from a Poisson radio source distribution is confirmed. A significant fraction of radio sources are associated with the supercluster-void network, which is composed of regular periodic structures on scales from 30 arcmin to one degree. A comparative study of the distributions and identifications of the RATAN-600 and 87GB surveys is performed. The data from this study are used to set limits on the cosmological parameter qo and the epoch of formation of large scale structures in the Universe. 相似文献
14.
Deep 1–49 cm surveys of the circumzenithal sky area performed using the RATAN-600 radio telescope allowed the spectral index of Galactic synchrotron emission in the 7.6–49 cm wavelength interval to be refined. The data obtained are inconsistent with the model of synchrotron emission adopted to interpret the results of the first year of the WMAP mission, which led to the hypothesis of the early secondary ionization of the Universe at redshifts Z > 10–30. New observations made with the RATAN-600 demonstrated the possibility of deep studies of the intensity and polarization of the microwave background (the E component) in ground-based experiments at short centimeter wavelengths. Galactic synchrotron emission may as well limit the possibilities of space- and ground-based studies of the polarization of cosmic microwave background radiation arising as a result of scattering induced by relic gravitational waves (the B component). The sky area studied with the RATAN-600 is intended to be used to interpret the PLANCK mission data in order to ensure a more detailed account of the role of the Galactic synchrotron emission. 相似文献
15.
The results of microwave observations of the polarized emission of active regionsmade with the RATAN-600 radio telescope are
used to develop the method for determining the structure of the magnetic field of these regions at coronal heights. About
1000-G-strong magnetic fields are observed in the solar atmosphere at rather high altitudes (from 10 to 25 Mm). This result
is confirmed fairly well by the ultraviolet observations of magnetic loops, it is consistent with earlier radio-astronomical
observations of the magnetic field at the height of the transition region, and it corresponds as well, if interpreted in terms
of the dipole magnetic field model, to the vertical gradients of the photospheric magnetic field. 相似文献
16.
V. M. Bogod P. M. Svidskiy E. A. Kurochkin A. V. Shendrik N. P. Everstov 《Astrophysical Bulletin》2018,73(4):478-486
We present the results of forecasting flare activity based on the data from microwave spectropolarimetric observations of active regions (ARs) obtained with the RATAN-600 radio telescope and the X-ray data from the GOES satellite as well as monitoring data. The method is designed for short-term (1–3-days) flare forecasts. Proton events are considered as part of the general flare problem. Obtaining a reliable forecast is a difficult process in view of the multi-parameter and multi-dimensional system of plasma parameter variations and multiple non-linear interconnections.We used a modified Tanaka–Enome criterion, as well a database of observational material collected over many years. The forecasting efficiency was analyzed depending on the threshold values of the criterion. We show that the quality of the radio astronomical forecast is determined by the level of sensitivity of the detector at short centimeterwavelengths and by the solar activity level. 相似文献
17.
In this study we continue our investigation of the radio sources located above the neutral line of the radial magnetic field in solar active regions, i.e., the so-called neutral line associated sources (NLS). The nature of NLS is still far from being understood. To study it, we use the spectroscopic capabilities of the new broadband polarimetric facility of the RATAN-600 radio telescope. We study the radio spectra of NLS sources in several solar active regions over a wide range of variations of their sizes. We find the NLS radio emission fluxes to be related to the gradient of the quasi-longitudinal magnetic field in the photosphere. We estimate the vertical positions of NLS relative to the cyclotron radio sources. We find fine spectral features in the NLS emission, which confirm the presence of a current sheet in their sources. We associate the appreciable lack of polarization in such sources with their location near the tops of the coronal arches. 相似文献
18.
Spectropolarimetric features of thermal cyclotron radiation of solar coronal loops and the possibility of interpretation of the observed reversal of the sense of polarization of centimeter and decimeter waves are discussed. To this end, thermal cyclotron radiation is computed in terms of the simplest model of a three-dimensional hot loop (a half-torus). Such a loop is shown to be capable of changing appreciably the properties of the radiation of a solar active region at centimeter and decimeter wavelengths. A detailed analysis is performed to determine the conditions under which the radiation spectrum of an active region containing a coronal loop may have a complex pattern with several maxima or relatively narrow-band cyclotron lines, and the sense of polarization may change several times in the wavelength interval considered. These conditions are modelled by such parameters as the structure of the magnetic field, electron density, and size of the loop. The results of the computations of two-dimensional brightness temperature distributions at different wavelengths for ordinary and extraordinary waves at fixed points of the loop and the integrated parameters of the flux and polarization of radiation in terms of the model discussed are reported. Cases are considered where the line of sight is crossed by one or two loops. The expected distribution of polarization across the source in the model considered is compared to the results of RATAN-600 observations of the solar active region AR 7962 made on May 12–14, 1996. 相似文献
19.
E. K. Majorova 《Astrophysical Bulletin》2008,63(1):56-69
In this paper we simulate a deep multi-frequency zenith-field sky survey on RATAN-600 (the RZF survey). In our simulations we use the 1.4-GHz sky images obtained in the NVSS survey. We convolved NVSS images with the two-dimensional power beam pattern of RATAN-600 and obtain simulated 24-hour scans of sky transits at all wavelengths of the RZF survey. For the 7.6-cm wavelength we analyze the effect of the image area size on the results of the simulation. We estimate the accuracy of the determination of source fluxes on simulated scans and derive the distributions of the spectral indices of the sources. We use the simulated scans to clean real records of the RZF survey at 7.6 cm. The standard error of the residual noise at this wavelength is about 1 mJy. 相似文献
20.
V. E. Abramov-Maksimov G. F. Vyalshin G. B. Gelfreikh V. I. Shatilov 《Solar physics》1996,164(1-2):333-343
In the present paper we present the results of measurement of magnetic fields in some sunspots at different heights in the solar atmosphere, based on simultaneous optical and radio measurements. The optical measurements were made by traditional photographic spectral observations of Zeeman splitting in a number of spectral lines originating at different heights in the solar photosphere and chromosphere. Radio observations of the spectra and polarization of the sunspot - associated sources were made in the wavelength range of 2–4 cm using large reflector-type radio telescope RATAN-600. The magnetic field penetrating the hot regions of the solar atmosphere were found from the shortest wavelength of generation of thermal cyclotron emission (presumably in the third harmonic of electron gyrofrequency). For all the eight cases under consideration we have found that magnetic field first drops with height, increases from the photosphere to lower chromosphere, and then decreases again as we proceed to higher chromosphere and chromosphere-corona transition region. Radio measurements were found to be well correlated with optical measurements of magnetic fields for the same sunspot. An alternative interpretation implies that different lines used for magnetic field measurements refer to different locations on the solar surface. If this is the case, then the inversion in vertical gradients of magnetic fields may not exist above the sunspots. Possible sources of systematic and random errors are also discussed. 相似文献